x=[0 5 5.05 5.3 5.8 5.9 6.3]
y=[0 0 10 9 16 18 20]

for i =length(x)-1:-1:1
    dx = x(end) - x(i);
    xm(i) = x(end)+dx;
end
xm = xm(end:-1:1);
x = [x xm];
y = [y y(end-1:-1:1)];

x= x/max(x);
n = 120;
[b, a] = yulewalk(n, x, y);
[H, w] = freqz(b, a);

figure(1)
plot(w/max(w), abs(H), x, y)
%figure(1)
%plot(x,y)